1. Field of Disclosure
The present disclosure of invention relates to a substrate for an electrowetting display device. More particularly, the present disclosure relates to an electrowetting display device having improved reliability.
2. Description of Related Technology
An electrowetting display device displays a desired image by selectively displacing parts of plural fluid layers where the parts include a polar (e.g., hydrophillic) fluid and a nonpolar (e.g., hydrophobic) fluid. Generally, the electrowetting display device includes a first substrate on which a plurality of pixel electrodes are formed, a spaced apart second substrate on which a common electrode is formed, a hydrophillic (polar, and thus electrostatically movable) upper fluid layer is interposed between the first and second substrates, and discrete amounts of a nonpolar (e.g., hydrophobic) fluid are disposed at each of the pixel electrodes where at least one of the fluids is dyed. When an appropriate voltage is applied between a respective pixel electrode and the common electrode, a normal surface tension state of the polar (e.g., hydrophillic) upper fluid is overcome and it is displaced so that the adjacent nonpolar (e.g., hydrophobic) fluid is also moved to make way for the electrostatically displaced upper fluid and this causes the corresponding pixel to transmit or block a supplied light. Thus, the electrowetting display device may display an image.
Processes of manufacturing the electrowetting display device includes fully filling the fluid layers (where “fluid” here means liquid) into a filling space defined by a containerizing structure disposed on the first substrate and combining the first substrate and second substrate under pressure. During this pressurized combination process, an undesired bursting of a sealant which combines the first substrate with the second substrate may occur if there an excess of internal pressure in the filling space during the process of bonding together (combining) the substrates. In addition, if the sealant does not burst, a middle portion of the electrowetting display device may be undesirably bulged by a non-contact remnant of the combining pressure so that a cell gap of the electrowetting display device may be non-uniform across its display area.
It is to be understood that this background of the technology section is intended to provide useful background for understanding the here disclosed technology and as such, the technology background section may include ideas, concepts or recognitions that were not part of what was known or appreciated by those skilled in the pertinent art prior to corresponding invention dates of subject matter disclosed herein.